1. Field of the Invention
The present invention relates to electronic chip components and methods for manufacturing electronic chip components, and in particular, to structures of outer electrodes located on outer surfaces of component bodies and methods for forming the outer electrodes.
2. Description of the Related Art
A known method related to the present invention is taught in Japanese Unexamined Patent Application Publication No. 11-283866. In this publication, terminal electrodes are formed on outer surfaces of bodies of chip components by the following steps: resistive films which will form terminal electrodes are formed with a resistive paste containing conductive particles of, for example, Ag, Cu, Au, Ni, Mn, Si, RuO2, SnO, ZnO, Cu2O, CuO, NiO, or TaN, and a curable resin, such as an epoxy resin, acrylic resin, melamine resin, phenolic resin, resol-type phenolic resin, unsaturated polyester resin, fluorocarbon resin, or silicone resin, by dipping, for example; the resistive films are cured; and Ni layers, and Sn layers or Sn—Pb alloy layers are optionally formed on the resistive films by plating. Capacitor-resistor (CR) composite components with an equivalent series resistance (ESR) ranging from 1 mΩ to 2,000 mΩ, which have sufficient capacitance functioning as the power-supply by-pass capacitance of power-supply circuits, can be fabricated by adopting the structure as described above.
In general, the above-described chip components are formed on wiring boards by soldering. Thus, terminal electrodes having good solderability are required. In general, the terminal electrodes are plated in advance with metals having high wettability to satisfy this requirement.
However, as described above, it is difficult to apply electroplating when the resistance value of the resistive films which will form the terminal electrodes is high. When the volume resistivity of the resistive films equals or exceeds approximately 5×10−3 Ω·m, it is difficult to apply electroplating. Thus, in practice, it is difficult to form metal-plated films having good wettability on the resistive films.
Instead of electroplating, non-electroplating or dry plating, for example, can be applied. In this case, however, additional steps such as covering the surfaces of component bodies with a resin are required so that plating films are deposited only on regions of the surfaces where terminal electrodes are to be formed.